As people turn their clocks back an hour on November 3 to mark the end of daylight saving time and return to standard time, they should remain aware of their sleep health and of potential risks associated with shifts in sleep patterns, according to a University of Calgary psychology professor who researches circadian cycles.
said Michael Antle, PhD, head of the psychology department and member of the Hotchkiss Brain Institute at the Cumming School of Medicine, University of Calgary, Alberta, Canada.
In an interview, Antle explained the science behind the health risks associated with time changes, offered tips to prepare for the shift, and discussed scientists’ suggestion to move to year-round standard time. This interview has been condensed and edited for clarity.
Why is it important to pay attention to circadian rhythms?
Circadian rhythms are patterns of physiologic and behavioral changes that affect everything inside the body and everything we do, including when hormones are secreted, digestive juices are ready to digest, and growth hormones are released at night. The body is a carefully coordinated orchestra, and everything has to happen at the right time.
When we start messing with those rhythms, that’s when states of disease start coming on and we don’t feel well. You’ve probably experienced it — when you try to stay up late, eat at the wrong times, or have jet lag. Flying across one or two time zones is usually tolerable, but if you fly across the world, it can be profound and make you feel bad, even up to a week. Similar shifts happen with the time changes.
How do the time changes affect health risks?
The wintertime change is generally more tolerable, and you’ll hear people talk about “gaining an hour” of sleep. It’s better than that, because we’re realigning our social clocks — such as our work schedules and school schedules — with daylight. We tend to go to bed relative to the sun but wake up based on when our boss says to be at our desk, so an earlier sunset helps us to fall asleep earlier and is healthier for our body.
In the spring, the opposite happens, and the time change affects us much more than just one bad night of sleep. For some people, it can feel like losing an hour of sleep every day for weeks, and that abrupt change can lead to car accidents, workplace injuries, heart attacks, and strokes. Our body experiences extra strain when we’re not awake and ready for the day.
What does your research show?
Most of my work focuses on preclinical models to understand what’s going on in the brain and body. Because we can’t study this ethically in humans, we learn a lot from animal models, especially mice. In a recent study looking at mild circadian disruption — where we raised mice on days that were about 75 minutes shorter — we saw they started developing diabetes, heart disease, and insulin resistance within in a few months, or about the time they were a young adult.